Questions tagged [regular-expressions]

Questions about the theory of regular expressions, both in the sense of Kleene's original definition and of POSIX regular expressions.

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Finding containing sets, within sets of sets

Let $s = \{\sigma_1, \sigma_2 \ldots \sigma_n\}$, where $\sigma_i \in \Sigma$, denote a set of alphabet characters. And $s \in S$ where $S$ denotes a set of sets. Given a new set $s' = \{\sigma'_1, \...
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Searchable finite field

Let $F$ be a large finite field, where the elements are strings of length $n$. We require, addition, multiplication, and division to be efficient (polynomial in $n$). We say that $F$ is searchable if ...
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Is it possible to simulate a regular expression using a single stack?

I understand that a regular expression can be converted to an equivalent DFA which can then be simulated. However, is it possible to simulate the regular expression directly with the aid of a stack ? ...
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Given a sequence find the shortest reg exp that generates it?

I'm looking for a way to find the smallest possible regular-expression that accepts a sequence. To make it interesting I don't want any stars(Kleene stars) and preferably no wildcards? For instance ...
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Can I show algebraically that this regular expression accepts all binary strings?

The task is to prove that (0+1)* and 0*(1.0*)* are equivalent. 1. http://rubular.com/r/K9Hp9tU6px 2. http://rubular.com/r/N8VpoEcch4 EDIT: Forgot that + was ambiguous here! I want to prove that the ...
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Writing a regular expression for character set $\Sigma = \{a,b,(,)\}$ that not have a parenthesis inside a parenthesis [closed]

Let character set $\Sigma=\{a,b,(,)\}$. I want to write a regular expression for the language $L$ that does not have a parenthesis inside a parenthesis. For example, $(abaab)(bbbaa) \in L$, while $(...

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